Enhanced telephony services are services provided on publicly accessible networks in addition to party-party calls, such as conference calls, call diversion, re-routing of calls and similar services. A particular difficulty with offering these services is the need to identify customers, and to recognise which service is required and to effect that particular customer's variation of the service.
Conventionally, such services are offered by replacing or reconfiguring the entire exchange. This is expensive, and generally produces a comparatively inflexible end result. Further, such services do not allow the possibility of the users themselves defining the services they require, nor generally such options as virtual private networks, closed user groups and dynamic detailed usage reports.
Prior art services which provide other than party-party calls on the PSTN have generally been rigid in services provided, alternative arrangements, and billing techniques. U.S. Pat. No. 3,668,317 to Vitalo describes a paging service which operates using a telephone number. This number only operates the paging service. Calling the number will then activate a pager and advise the caller that the customer has been paged. Only the called party could be billed for this service.